1. Field of the Invention
The present invention relates to a radiation detecting panel and a radiographic detector.
2. Description of Related Art
Radiographic detectors or flat panel detectors (FPDs) have been developed. Such detector includes a scintillator and a radiation detecting panel. The scintillator converts incident radiation to light, such as visible light, and the radiation detecting panel includes a two-dimensional matrix of photoelectric transducers for detecting the converted light, such as photodiodes, disposed on a substrate (for example, refer to Japanese Patent Application Laid-Open Publication Nos. 2009-219538 and 2010-43887 and U.S. Pat. No. 6,172,371). The light incident on the photoelectric transducers are converted to electric chargers, and the generated electric chargers are extracted to detect as electrical signals the information carried by the incident radiation from a subject.
For example, as illustrated in FIG. 23, a radiographic detector may include a radiation detecting panel 100 that includes a two-dimensional matrix of photoelectric transducers 102 disposed on a device substrate 101 and a scintillator 104 bonded to a scintillator substrate 103 so as to face the photoelectric transducers 102 from above (for example, refer to Japanese Patent Application Laid-Open Publication Nos. 2003-75543, 2004-61172, and 2010-25780).
In the radiographic detector, the radiation detecting panel 100 is accommodated in a housing (not shown in the drawing). Regarding the relative positions of individual components in the radiographic detector and the radiation detecting panel described below, the vertical direction is determined in a state in which the radiographic detector and the radiation detecting panel are disposed such that the scintillator is disposed above the photoelectric transducers. It is noted that the positions of the components vary in both the vertical and horizontal directions with a change in the posture of the radiographic detector.
As illustrated in FIG. 24, which is an enlarged view of FIG. 23 including the photoelectric transducers 102, the scintillator 104 covering the photoelectric transducers 102 and a smoothing layer 105 smoothening the bumps on the surfaces of the photoelectric transducers 102 may be bonded together with a bonding layer 106 composed of a resin, in some cases. Reference numeral 107 shown in FIG. 24 illustrates wiring such as a signal line associated with the photoelectric transducers 102.
In a radiation detecting panel 100, for example, having a structure illustrated in FIGS. 23 and 24, the distance between the photoelectric transducers 102 and the scintillator 104 may vary due to softening of the cured bonding layer 106 caused by an increase in the temperature of the radiation detecting panel, for example. As a result, the light generated in the scintillator 104 by converting the incident radiation may leak out to the photoelectric transducers 102 other than the photoelectric transducer 102 directly below the position from which the generated light is emitted, changing the sharpness of the resulting radiographic image.
The separation of the bonding layer 106 from the scintillator 104 and/or the smoothing layer 105 adjoining the photoelectric transducers 102, for example, due to warpage of the radiation detecting panel reduces the geometric precision of the photoelectric transducers 102 and the scintillator 104. As described above, a large amount of light from the scintillator 104 may leak out to the photoelectric transducers 102 other than the photoelectric transducer 102 directly below the incident position from which the generated light is emitted, reducing the sharpness of the resulting radiographic image.
As will be described below, any other resin layer having a different function may be disposed between the scintillator 104 and the smoothing layer 105 adjoining the photoelectric transducers 102 in place of the bonding layer 106. In such a case, the softening or separation of the resin layer may cause various drawbacks, such as low sharpness of the radiographic image, similar to that described above.